<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <!-- <link rel="stylesheet" href="./lib/animate.css"> -->
    <style>
        .ball {
            width: 15px;
            height: 15px;
            border-radius: 50%;
            background: rebeccapurple;
        }
    </style>
</head>

<body>
    <div id="app">
        <input type="button" value="加入购物车" @click="flag=!flag">
        <transition @before-enter="beforeEnter" @enter="enter" @after-enter="afterEnter">
            <div class="ball" v-show="flag"></div>
        </transition>

    </div>
    <!-- <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script> -->
    <script src="./lib/vue-2.4.0.js"></script>
    <script>
        var vm = new Vue({
            el: '#app',
            data: {
                flag: false
            },
            methods: {
                beforeEnter(el) {
                    el.style.transform = 'translate(0,0)'
                },
                enter(el, done) {
                    el.offsetWidth
                    el.style.transform = 'translate(150px, 450px)'
                    el.style.transition = 'all 1s ease'
                    done()
                },
                afterEnter(el) {
                    this.flag = !this.flag
                    // el.style.opacity=0.5

                    //vue吧一个完整的动画，使用钩子函数，拆分为了两部分
                    //我们使用 flag 标识符 ，来表示动画的切换
                    //刚开始，flag=false --> true -> false
                }
            }

        })
    </script>
</body>

</html>